Evolution is supported by evidence found throughout living systems. This lesson focuses on three important sources: the fossil record, anatomical structures, and embryonic development. Together, these sources reveal how organisms have changed over time and how different species can share common ancestors.
Fossils are preserved remains or traces of organisms from the past. By determining and comparing fossil ages, scientists construct the fossil record: evidence of which organisms lived at different times and how their forms changed across millions of years.
All flashcards
What is the fossil record?
The fossil record is the evidence from fossils, organized by age and occurrence, that documents organisms from the past and changes in their forms over time.
What does a transitional fossil show?
It shows intermediate anatomical features between earlier and later forms, helping document evolutionary change within a lineage.
How do homologous structures support evolution?
Homologous structures share a basic anatomical pattern because they were inherited from a common ancestor, even if their shapes and functions have changed.
What is a vestigial structure?
A vestigial structure is a reduced or leftover feature inherited from ancestors in which it was more developed or had a different role. It may still have a function.
How can embryology provide evidence of relatedness?
Species may share features during early development, such as gill slits in vertebrate embryos, even if those features change or disappear before adulthood.
Quiz questions
What best explains the distribution of the plant family Proteaceae across Australia, southern Africa, and South America?Answer: The family was present across Gondwana before its landmasses separated.
What does it mean for a species to be endemic to a region?Answer: It occurs naturally only within that particular region.
What does greater DNA sequence similarity between organisms typically indicate?Answer: They share a more recent evolutionary history.
Why does the near-universality of DNA and the genetic code support common ancestry?Answer: Shared genetic systems are consistent with inheritance from common ancestors.
How can gene duplication contribute to the evolution of a new protein function?Answer: One copy can retain its original role while the other accumulates changes.
Based on Concepts of Biology by Samantha Fowler, Rebecca Roush, James Wise (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.